The present invention relates to a new and improved method of, and apparatus for, connecting a yarn or other filamentary material--hereinafter simply referred to generically as "yarn"--and for forming a yarn reserve at a bobbin tube or sleeve. This invention also relates to apparatus for the performance of such method.
Generally speaking, there is taught a method for connecting a yarn and for forming a yarn reserve at a bobbin tube or sleeve during the bobbin change after the removal of a full bobbin at a spinning location of a spinning machine, especially at an open end-spinning machine briefly designated as an OE-spinning machine, wherein the yarn, during the bobbin change, is continuously further produced by the spinning location and after removal and servering the full bobbin or package, is sucked by means of a guide channel, through an infeed element which can be manually seized and moved, into a stationary suction opening. Thereafter, the infeed element is manually moved, while entraining the throughpassing yarn, towards the new empty bobbin tube, and brought into a position relative thereto where the yarn arriving at the infeed element is received by a yarn take-up or receiving element provided at the new bobbin tube. Upon severing the part of the yarn located in the yarn infeed element and travelling towards the suction opening, the yarn is wound onto the bobbin tube.
Now in German Pat. No. 26 22 119 there is taught to the art a method and apparatus of the previously mentioned type, wherein the infeed element is constructed as a tubular section, the interior of which forms the guide channel through which travels the yarn. At a bobbin holder, carrying that end of the new bobbin at which there should be connected the yarn and where there is to be formed the yarn reserve, there is provided a guide disc. This guide disc is oriented perpendicular to the bobbin axis and at a slight spacing from the yarn reserve end of the bobbin tube or bobbin and protrudes radially outwardly past the periphery of the bobbin tube. Further, this guide disc has an essentially circular-shaped outer edge extending over part of its circumference. This circular-shaped outer edge merges into a radially inwardly extending guide edge portion at a location thereof where a holder arm of the bobbin holder extends away from the disc. The guide edge portion or part then continues in the form of a further arc-shaped part of smaller diameter over the therewith merging region of the disc. The radial guide edge is also equipped with an inclined surface which essentially extends at an inclination outwardly from the inner surface confronting the tube and from the tube end with regard to the outer surface. At the guide disc there is provided approximately at the side situated diametrically opposite the end of the holder arm of the bobbin holder, a guide plate having a guide section which constricts markedly inwardly from an edge of such plate. Furthermore, a rod or blade-shaped spring is attached to the bobbin holder. The free spring end resiliently bears at the surface of the guide plate confronting the bobbin holder, adjacent a cut-out at its region located closer to the bobbin. The bobbin or package tube is provided at that end where there is to be formed a yarn reserve with a roughened portion extending completely about its periphery and in the form of grooves directed essentially parallel to the generatrices or surface lines.
With this prior art method and the associated equipment the connection of a continuously infeed yarn with a new empty bobbin tube or bobbin is accomplished in such a manner that after mounting the new empty tube at the bobbin holder the tubular-shaped infeed element, which initially is located in front of the stationary suction opening through which there is sucked-up the yarn, is manually seized and moved towards the new bobbin tube. The infeed element forms a guide tube in the direction of the one end of which there travels the yarn delivered by the spinning machine and through the other end of which such yarn travels, after passing through the tube, towards the stationary suction opening. The infeed element is then manually brought into such a position relative to the new bobbin tube that the part of the yarn travelling from the spinning machine to the infeed element, at the region of the cut-out of the guide plate arrives at the guide disc of the bobbin holder and subsequently comes to bear at the inclined surface of the radial guide edge of the guide disc. Now if then the infeed element is manually moved somewhat towards the bobbin holder, then the incoming yarn is introduced into the narrowest base part of the tappering or narrowing guide cut-out of the guide plate. At the same time the yarn arrives between the rod-shaped or blade-shaped spring and the guide plate--which spring bears against the inside of the guide plate--and by virtue of the prevailing clamping action is exposed to increased friction. Consequently, the part of the yarn which extends from the cut-out in the guide plate to the infeed element is exposed to greater tension. Now if the infeed element is still further moved towards the bobbin holder, then the yarn part located between the guide plate and the radial guide edge comes to bear at the roughened end of the tube or sleeve. Viewed in a direction perpendicular to the tube axis, the yarn thus travels at a slight inclination with respect to the tube over the tube edge towards the outside. Thereafter, by means of a cutter or knife arranged at the infeed element and moved into and transversely with regard to the tubular section, the yarn passing through the tubular section or tube is cut or severed. The part of the yarn travelling onto the tubular section and located forwardly of the cutting location, situated between the contact point of the yarn with the bobbin tube and the infeed element, is entrained by the bobbin tube owing to rotation thereof and forms a free yarn end protruding past the edge of the bobbin tube. This free yarn end is wound-up during the further rotation of the bobbin tube amounting to a number of yarn coils or windings which are formed from the yarn which is infed via the cut-out in the guide plate. The entrainment of the yarn by the bobbin tube is accomplished by virtue of the friction prevailing between the roughened outer surface or jacket of the revolving bobbin tube and the yarn bearing thereat.
With this known method it is necessary to provide a specially constructed bobbin holder having a guide plate and guide disc with contact edge, so that this state-of-the-art method cannot be used with already existing equipment, or at the very best only by carrying out considerable and costly structural modifications. Moreover, the successful connection of the yarn with the bobbin tube, according to such prior art method, is essentially dependent upon the care and dexterity of the operator, who must move the tubular-shaped infeed element past the bobbin tube into a position where the incoming yarn properly comes into contact with the bobbin tube. Since such movement must be accomplished without the aid of any guide means, and thus the infeed element must be brought into a certain spatial position without any support and freely manually, there is a relatively great danger that the yarn connection operation will not be satisfactorily accomplished due to improper positioning of the infeed element.